Getting solid data on the consistency of cement
Magna Projects and Instruments has been licensed to develop and market a rugged machine for the Tattersall Two-Point Workability Test for fresh cement and concrete
Magna Projects and Instruments has been licensed by Heriot-Watt University and the University College of London (UCL) to develop and market the Tattersall Two-Point Workability Test (TTPT) for fresh cement and concrete.
This instrument, which was developed over the past 25 years of so at Sheffield University by Dr Geoff Tattersall, is designed to provided some solid engineering data on the consistency of mixes such as cement and concrete pastes.
Such data is vital for batch-to-batch quality control, and to ensure, for example, that unsuitable batches of material are not inadvertently poured onto such structures reinforced concrete buildings, thereby creating potential weak spots.
Cement and concrete pastes flow in a distinct way, behaving as "Bingham Fluids".
That is to say, they do not start to flow until a characteristic "Yield Stress" had been exceeded (a useful feature, as this allows the mix to stay in position until it sets), and then they flow in a linear or Newtonian manner, ie the shear stress (force) increases proportionally to the shear rate (speed).
Thus, the material may be characterised by the Yield Stress and by the slope of the ensuing straight line, which is, in fact, the plastic viscosity.
The TTPT is a rugged machine which may be used in the research and development or QA/QC laboratory or on site.
The principle of operation is to rotate a paddle in the sample - typically 20 - 30 litres - and to measure the torque required to rotate the paddle over range of speeds.
The torque vs speed curve then enables the Two Points to be evaluated.
The instrument may be operated in relative mode, or may be calibrated using materials of known rheology.
Two paddle geometries are available - a helical paddle, which rotates centrally, or an H-bladed paddle which rotates on a planetary gear for materials to avoid cavitation in susceptible formulations.
The instrument is fully guarded, and is automated so that it may be operated in constant speed, staircase or ramp speed modes.
Torque is measured by monitoring the oil pressure in the drive chain, and this is displayed on a panel-mounted pressure gauge and recorded by a computer via a pressure transducer.
Similarly, speed may be monitored and controlled by the computer, or may be changed manually.
Shear pins protect the drive against inadvertent overloads due, for example, to clumps of aggregate.
The TTPT may be hosed clean if required.
Not what you're looking for? Search the site.
Articles by product category
- Consultancy and Services (903)
- Machine Building (4,517)
-
Engineering Design Software (6,179)
- Engineering Design Software (12)
- 2D CAD software (200)
- 3D CAD software (1,157)
- FEA and structural analysis software (369)
- Fluid, thermal, noise, vibration software (334)
- Simulation, modelling, validation software (914)
- Rendering, visualisation, styling software (196)
- Materials design and moulding design software (151)
- Process, instrumentation, automation software (258)
- Electrical design software (164)
- Publishing and documentation software (229)
- Maths, charting, statistics, QA software (317)
- Data, document management software (310)
- CAM, CNC, production management software (568)
- File conversion software, data capture (351)
- PLM and collaboration software (649)
-
Drives, Motors and Controls (3,361)
- Drives, Motors and Controls (1)
- Precision Motors and Gears (411)
- Industrial Drives/Controls (1,276)
- Linear Drives and Motors (114)
- Industrial Motors (497)
- Stepper and Servo Drives, Motors, Controls (1,060)
- Small Mechanical Components, Joining, Tools (1,975)
-
Control and Instrumentation (5,028)
- Plantwide control (1,324)
- Plant- and Machine-Wide Communications (1,174)
- Smaller-Sized PLCs (387)
- CNC and Motion Controllers (184)
- Mid-range and Large PLCs (201)
- Power Supplies, Uninterruptible Power (562)
- HMIs/Operator Interfaces (294)
- Logic Controllers, Timers and Relays (96)
- Cabling, Conduit, Signal Conditioning (806)
-
Monitoring, Measurement and Quality (5,459)
- Monitoring, Measurement and Quality (1)
- Data acquisition Software and Communications (494)
- Data Acquisition Hardware and PC I/O Boards (472)
- Electrical and Electronic Testing, PAT Equipment (630)
- Form/co-ordinate, optical, vision instruments (703)
- Gauges, Indicators and Instruments (440)
- Data loggers (422)
- Materials testing equipment (421)
- Telecomms/network test equipment, software etc (154)
- Testing and Calibration Services and Information (500)
- Testing, analysing and monitoring equipment (1,222)
-
Electrical and Electronic Equipment Design (4,160)
- Batteries, chargers and circuit protection (555)
- Connectors, Terminals, Busbars, Slip Rings (679)
- Enclosures and Equipment Cooling Fans (709)
- Knobs, Handles and Enclosure Hardware (420)
- PCs and Embedded Systems (798)
- Electrical and Electronic Subassemblies (369)
- Electrical and Electronic Components (630)
-
Materials and Processing (2,963)
- Materials and Processing (5)
- Materials and components (2,215)
- Rapid Prototyping (458)
- Materials processing and testing (285)
-
Engineering Industry News, Resources (6,093)
- Engineering Industry News, Resources (4)
- Engineering Business News, Views (388)
- Engineering Exhibitions, Events (562)
- Engineering Conferences (425)
- Engineering Seminars (400)
- Engineering Industry Developments, Awards (633)
- Engineering Guides, Newsletters (349)
- Engineering Recruitment, Employment (219)
- Engineering Training Courses (433)
- Engineering Education, Resources, Standards (838)
- Engineering Industry Reports, Surveys (597)
- Electronic Resources for Engineers (278)
- Health and Safety Legislation (402)
- Health and Safety Strategy, Risk Assessment (113)
- Health and Safety Consultancy, Software (175)
- Health and Safety Events, Training, News (277)
-
Powertrain Design (3,598)
- Powertrain Design (2)
- Bearings (939)
- Chains and belts (326)
- Gears, brakes, couplings and engines (1,441)
- Hydraulic Components (471)
- Lubricants (418)
-
Capital Equipment (3,387)
- Capital Equipment (1)
- Manufacturing Machinery and Plant Equipment (468)
- Production line blowers and fans (62)
- Compressors and Air Treatment (510)
- Electronics Manufacturing, Tools, Instruments (192)
- Electrical hardware (131)
- Machinery and Production Equipment (1,093)
- Robotics, Handling and Storage (930)
-
Sensors (7,080)
- Sensors (8)
- Accelerometers and Vibration Sensors (427)
- Loadcells, Force Sensors, Torque Sensors (699)
- Pressure sensors (621)
- Flowmeters and Flow Sensors (618)
- Level Sensors and Leak Detectors (527)
- Linear Position Sensors (399)
- Rotary Position, Tilt and Angular Sensors (546)
- Proximity Sensors (700)
- Gas, Chemical, Radiation, Magnetic Sensors (284)
- Humidity and Environmental Sensors (152)
- Temperature sensors (612)
- Vision and Colour Sensors (1,384)
- Barcode Sensors (103)
- Valves, Pumps, Process Hardware (3,623)